1. Field of the Invention
This invention relates to traps and filters for attachment over the gratings on sanitary, storm or catch basin inlet drops.
2. Description of the Related Art
When streets are under construction, the catch basins for the sewers can fill up with all kinds of debris during rains. When construction in the area is not complete there are many objects in the area that can be washed into the newly installed sewer and clog it up, whereas after construction when the area is in finished condition, landscaped, fully paved, and construction related debris is removed there are fewer objects which can be washed into the catch basin and clog up the sewer.
In the past, bales of hay would be placed in the water flow path to an inlet drop to filter out debris; however silt and other smaller particles would go around or through the bales and clog the sewer as would some of the hay. The bales were subject to moving, not being placed properly to block all of the flows, being eaten by deer, rabbits or other animals or posing a hazard as rats, mice or other pests used the hay bales for nests. Further, the bales could easily come apart and loose their effectiveness as debris flow barriers.
Other attempts to keep debris and silt out of sewers were by use of silt fences. A silt barrier material staked across a flow path was supposed to stop silt and debris from entering an inlet drop into a sewer. Such debris fences had limited success as water flows carrying debris could undermine the fence, go around the fence or destroy the fence.
One solution was to place a slotted barrel like member over the inlet drop and wrap it with a silt screen material to let water through but keep silt and debris out. However the barrel was not secured to the inlet drop and could easily be removed from its protective position thus letting silt and debris into the sewer.
Another solution was to provide a silt barrier material around the inlet drop to prevent water and debris from entering the sewer and stake the silt barrier material in place. However the staked out sheeting would not remain in place when the pressure of large amounts of water where present. To help hold the sheeting in place a cylindrical framework like a bicycled wheel at the top and bottom of a sheet was used to support a sheet of plastic and a central axis rod holding the wheel would be used to separate the wheels and attach the rod to the grate over the inlet drop. However it was difficult to set up the sheet around the barrier to keep the water out of the inlet drop as there was not a good seal of the silt barrier material to the frame, and the silt barrier material was subject to tearing, holes being poked through and other damage due to lack of support.
It is desired to have a debris and silt barrier that allows water therethrough into an inlet drop while being strongly secured to the grating over the inlet drop and having apertures for allowing water through while preventing debris through and supporting a silt guard to prevent silt from entering the sewer. The barrier should be easy to install and durable enough to withstand torrents of water with debris therein. The barrier should also completely cover the inlet drop to prevent accidents where people trip or fall on the inlet drop. The barriers are also used for clearly marking the position of the inlet drops.